In maintenance of plant systems or IT (Information Technology) systems, a maintenance plan is drawn up based on a risk matrix that is generated by risk analysis of the system. The risk matrix is a matrix that represents a magnitude of a risk involved in each event, such as an accident or a failure of a system, with a likelihood level that indicates how likely the event is to occur and an impact level of the event. The risk matrix indicates combinations of likelihood and impacts for a variety of events that will possibly occur in a system. Accordingly, the maintenance is reinforced for events with greater magnitudes of risks (with greater levels of likelihood and impacts) by increasing the number of inspections for the events, for example.
In this way, to analyze risks in a system, it is necessary to classify events that will possibly occur and define likelihood and an impact for each classified event. A technique for analyzing a risk in a system is disclosed, for example, in PTL 1. The technique described in PTL 1 calculates an impact of an event described in risk items using risk analysis models that are created based on risk cases.
It is noted that, as a relevant technique, PTL 2 discloses a technique that determines a position on a risk assessment matrix corresponding to a current operation condition of equipment, and displays a guidance corresponding to the determined position. Further, PTL 3 discloses a technique that generates a system model using time-series performance information of a system, and monitors the system using the generated model. PTL 4 discloses a technique for detecting a system failure based on destruction of a correlation. PTL 5 discloses a technique for detecting system performance degradation based on destruction of a correlation.